Photo-engraving process



Sept. 27, F. ST OCKINGER PHOTO ENGRAVING PROCES S Filed May 18. 1926 INK 1/4; F-mA/E ETC/IEO come/r FLA TE 0 MI/r WWW/12% wrm FLA r5 /mwz 57'0C/t/N6EK INVENTOR 4 ATTORNEY.

Patented Sept. 27, i927.

UNITED STATES FRANZ STOOKINGER, OF NEW YORK, N. Y.

rnoro-imenavme rnocuss.

Application filed Kay 18,

5 which will give the maximum efficiency, andv which will reduce the cost of production to a minimum. p

lPrinting plates used in lithography and ofiset work and intended for printing in produced by a series of steps which are well known and require no discussion here. It is well known to those skilled in the art that present methods are far from (fierfect, the dificulties being due to metho transference, delicate handling requlred of the finished plates, and mainly to the short life of such platesin the presses.

Briefly stated, the present invention comprehends a process of producing ofl'set print ing plates from photoengravers cuts which consists in, first rolling 011' a half tone etched copper plate with ink, then making an impression from the inked plate onto the surface of a sheet of crystal plate glass, the result being a positive impression, which is thereafter reproduced on the sensitive surface of a zinc plate. The zinc plate is developed and deeply etched and finally provided with a deposit of varnish or other similar medium. Further treatment of the plate removes all of the varnish except that de posited on the hollows of the engravings. The plate after being cleaned andrpollshed is run 05 with ink and an impression made on the blanket of an offset press in the usual manner. The strength and character of the impression on the ofi'set blanket, resulting from the process, make it possible to utilize substantially any grade and surfaced paper upon which impressions may be taken. The

life of the oflset plate is considerably len'gthened because the deeply etched subjectin half tone is subjected to practically no wear,

while ordinary printing plates, comprising a raised printing surface, become worn in the high lights and as a consequence no im-\ pression is made on the offset blanket in the course of a long run.

The object obtained by the present invention has been sou ht by "others, and so far as l am aware t e closest approximation to my method is one in which a sheet of celluloid or solidified transparent gelatin is utilized as a reproducing body to produce a one color or in combinations of colors are of prooi V 1926. Serial No. 109,878.

printin plate, but the inherent nature of celluloid and the steps necessary to carry out the process in the use of celluloid render the prior art method impractical. One of the essential difficulties with the prior art method is due mainly to the action of certain chemicals on the celluloid, which warps and becomes otherwise distorted under the treatment. I

After exhaustive experiments with the object of overcoming the difficulties above pointed out, I concluded that the solution of the problem was to be found in the use of a proper'mediu'm to reproduce the half tone copper-plate onto the offset zinc plate. G0-

mg a step further and taking into account the fact that while the celluloid is' transparent, with the use of such proper medium, the celluloid still became distorted under the chemical treatment to which it was subjected, thesolution again pointed in the direction of a diiferent material than celluloid. I then discovered that by replacing the" ister where more than one color is used in x the offsetwork, and because of the weight of the impressions obtained from the plates, each copy of the run of prints, has-a depth of color and shade radation which it is not possible to obtain y any of the processes now used in this art.

The present invention consisting of the novel methods, steps and processes hereinafter described and claimed, will be more easily comprehended if taken in connection with the illustrations in the accompanying drawings, in which, Figure l is a fragmentary perspective view of a copper plate having an object etched in relief on its surface, the same having been rolled off with a printing ink as a step in the present process; Figure 2 isa substantially cross sectional view of the inked copper plate superimposed on the surface of a sheet of crystal glass; Figure 3 is a fragmentary erspective 'view of a zinc negative obtained 4 is a substantially'sectional view through exposure of li through the glass repr notion and g e the final etched zinc negative plate illustrating the deposit of varnish over the bottom walls of theetched dots.

Tn carrying out my improved process, a half tone copper plate isetched so as to render the subject in relief, the plate being similar to those used ordinaril for typographi lamp-black .to the inked surface and a subi I design scribed above are for all practical purposes perfect reproductions of the original plates, so that a plurality of printing plates pro .duced to reproduce in two or more colors are sequent application of talcum to remove surplus ink, places the crystal reproducing body in readiness for use. A zinc plate is then pre ared and its sensitized surface is placed un er the crystal plate. An exposure is then made and the zinc plate developed and etched to a depth of substantially .002 013003 of an inch. The result of these steps'is a plate'having a design represented by holows corresponding to the spaces between the lines of theprocess screen. The etched surface of thezine plate is finally given an ap plication of ink shedding varnish and then treated to remove the varnish from the non ortion. This treatment leaves a film of t e varnish in the hollows of the engravings. The plate is then ready for an I HIP ho lication .of ink, which is confined .to the lows of the en raving, and which may be drawn off from t e varnish film and deposited on the offset blanket of a press'inthe usual manner. I Negatives produced after the manner demsured perfect register; The finished negas ftives having the deeply etched hollows are not destroyed by allowing theink to become dry on the surface, as is the casewith' plates having the printing surface'in relief, because 'in the event that dry-ink is allowed to adhere to the printing surface all that is necessary to do is to washandetch the surface again making the plate ready for the press.

In the accompanying, drawings, I have il-' lustratively exemplified asimple etched plate, a crystal late having an impression of the design of t e etched plate, and a negaplate. The half tone etched copper,

tive

plate s 10, the crystal plate 11, and the neglaif tive'zinc printing plate 12. The inked sign on the crystal plate 11 is 13 and the .varnish deposit in the hollows of th engraving the zinc plate 12 is 14.

J surface. s

i Leeaeaa Having set forth of what my invention consists and the, nature in which it is practiced, what I claim and desire by Letters Patent is l. The process of producing offset printing 7() plates from photoengravers cuts, which consists in making an ink impression ofa design onto a rigid transparent plate, thereafter exposing a sensitized surface of a printing plate under said transparent plate, and treatipg the exposed surface to produce an ink shedding printing surface. v

2. The process of producing ofiset printing plates from photoengravers cuts, which consists in preparing a plate with the design etched in relief, then rolling ofl the design with ink, making an impression of said inked design'onto a rigid transparent crystal plate,

thereafter exposing a sensitized surface of a printing plate under said transparent plate,

and finally treating the exposed surfa'ceto' produce an ink shedding printing surface.

3. The process of producing offset printing plates from photoengravers cuts, which consists in preparing a plate'with the design etched in relief, then rolling off the design with ink, making an'impression of said inked design onto the surface of a rigid transparent crystal plate, applying an opaque substance to the ink impression on the transparent plate and then removing the surplus opaque substance from the non-design surface of the transparent plate, preparing a printing plate" and exposing the sensitized surface of same under the transparent plate, 1

and thereafter treating the exposed surface to produce an ink shedding printing surface.

\ 4r. "The process of producing an offset printing plate from photoengravers cuts whlch bonsists in. preparing a half tone-etched 165 plate having the design in relief, rolling off the design with a stijf ink, preparmg'a rigid transparent crystal plate, then impressing said inked plate onto the transparent crystal plate -to transfer the ink design to no the surface of said transparent plate, applying opaque powder to the surface of the transparent plate and removing the surplus from the non-design portions of the sur- I. Q face, preparing an offset printing plate,

thereafter exposing the sensitized surface of theoifset plate .under the transparent 3 plate, and finally. treating the exposed surface to produce an ink shedding printing 5. The process of producing offset print ing plates from photoengravers cuts, which consists injprinting a designin h'alf'tone onto the surfaces of a rigid transparent reroducing body thereafter utilizing said 125 ody to produce a printing plate, and final- 1y treating the printing plate to produce an 'ink shedding filmxin the hollows of the engraving.

6. The. process of producing offset nrint-' ing plates from photoengravers cuts, which consists in preparing a half tone plate with the design etched in relief, rolling off the de sign with, ink, impressing the inked plate on the surface of a transparent glass plate, treating the impression to intensify the design, preparing a zinc plate and e ing the sensitized surface thereof under sai glass plate, preparing the exposed surface to produce a printin surface having a design 10 tions in the hollows of the etched engraving.

In testimony whereof I aflix my signature.

FRANZ STOCKINGER. 

